Conventional work machines, such as loaders and excavators, are becoming increasingly automated. Instead of a human operator manipulating various aspects of the work machine, such as raising and lowering the bucket, and backing the work machine out from a pile of material, electronic controllers control an increasing number of the functions of the work machine with minimal human input. It is increasingly desirable to automate the work cycle of a work machine to decrease operator fatigue, to more efficiently load the bucket, and to permit its use where conditions are unsuitable for a human operator.
Many of the functions of the work machine are dependent on the condition of the material that the work implement is moving or loading. For example, when a bucket loader loads a pile of loose or soft material, the bucket will typically fill more quickly than for a hard packed material.
Some automatic systems adjust the operating characteristics of the work machine depending on the material hardness. Typically these systems collect data during one work cycle, e.g., loading a bucket with material from a pile and backing away from the pile, and evaluating it. Based on the collected data, the system will adjust the characteristics of the work machine for the following work cycle.
These systems work well as long as the material conditions are uniform from one work cycle to the next. Material conditions, however, frequently vary between work cycles. For example, a bucket may be digging into a hill composed of two materials having different hardnesses, such as clay and sand. During the initial dig pass, the bucket may predominantly encounter the clay, while during the next pass, predominantly sand is encountered. Thus, the bucket will fill at different times for these two dig passes, and the operating characteristics for the first work cycle, e.g., the point at which the bucket is considered to be full, are not the optimum operating characteristics for the second work cycle.